JPEG'd contest - securerodd's results

JPEGd Contest

April 12, 2022

@securerodd

Gas Optimizations

1. Refactor Beggining of borrow() in NFTVault.sol

The check performed in the beginning to see if the positionOwner is not yet set is semi-redundant as it is reperformed later in the code to determine if a position should be opened. This can be refactored to increase gas efficiency.

Current code:

        accrue();

        require(
            msg.sender == positionOwner[_nftIndex] ||
                address(0) == positionOwner[_nftIndex],
            "unauthorized"
        );
        require(_amount > 0, "invalid_amount");
        require(
            totalDebtAmount + _amount <= settings.borrowAmountCap,
            "debt_cap"
        );

        if (positionOwner[_nftIndex] == address(0)) {
            _openPosition(msg.sender, _nftIndex);
        }

Gas:

 ___________________________________________________________________________________________
| Contract          ·  Method              ·      Min    ·      Max    ·        Avg   ·     |
 ___________________________________________________________________________________________
| NFTVault          ·  borrow              ·     142891  ·     428260  ·      402204  ·     │
 ___________________________________________________________________________________________

Recommended code:

        accrue();

        require(_amount != 0, "invalid_amount");
        require(
           totalDebtAmount + _amount <= settings.borrowAmountCap,
           "debt_cap"
        );

        if (positionOwner[_nftIndex] == address(0)) {
           _openPosition(msg.sender, _nftIndex);
        }
        else {
            require(
                msg.sender == positionOwner[_nftIndex], 
                "unauthorized"
            );
        }

Gas:

 ___________________________________________________________________________________________
| Contract          ·  Method              ·      Min    ·      Max    ·        Avg   ·     |
 ___________________________________________________________________________________________
| NFTVault          ·  borrow              ·     142868  ·     427851  ·      401821  ·     │
 ___________________________________________________________________________________________

2. For Loop Refactoring

The for loops used throughout the codebase can benefit from one or more of the following gas saving techniques:

1. Storing the array length in a local variable in memory before comparisons
2. Using a prefix increment instead of postfix

Current Code in harvest() function of StrategyPUSDConvex.sol:

            for (uint256 i = 0; i < rewardTokens.length; i++) {
                uint256 balance = rewardTokens[i].balanceOf(address(this));
                ...
            }

Gas:

 ___________________________________________________________________________________________
| Contract          ·  Method              ·      Min    ·      Max    ·        Avg   ·     |
 ___________________________________________________________________________________________
| StrategyPUSDConvex·  harvest             ·     635854  ·     747869  ·      691862  ·     │
 ___________________________________________________________________________________________

Recommended logic:

            uint rewardTokenLen = rewardTokens.length;
            for (uint256 i = 0; i < rewardTokenLen; ++i) {
                uint256 balance = rewardTokens[i].balanceOf(address(this));
                ...
            }

Gas:

 ___________________________________________________________________________________________
| Contract          ·  Method              ·      Min    ·      Max    ·        Avg   ·     |
 ___________________________________________________________________________________________
| StrategyPUSDConvex·  harvest             ·     635762  ·     747777  ·      691770  ·     │
 ___________________________________________________________________________________________

Example nested for loops in the initializer of NFTVault.sol:

        for (uint256 i = 0; i < _typeInitializers.length; i++) {
            NFTCategoryInitializer memory initializer = _typeInitializers[i];
            nftTypeValueETH[initializer.hash] = initializer.valueETH;
            for (uint256 j = 0; j < initializer.nfts.length; j++) {
                nftTypes[initializer.nfts[j]] = initializer.hash;
            }
        }

Recommended logic:

        uint256 typeInits = _typeInitializers.length;
        for (uint256 i = 0; i < typeInits; ++i) {
            NFTCategoryInitializer memory initializer = _typeInitializers[i];
            nftTypeValueETH[initializer.hash] = initializer.valueETH;
            uint256 nftsLength = initializer.nfts.length;
            for (uint256 j = 0; j < nftsLength; ++j) {
                nftTypes[initializer.nfts[j]] = initializer.hash;
            }
        }

Other locations that could benefit from some or all of these suggestions:

• balanceOfJPEG() in StrategyPUSDConvex.sol
• The constructor in StrategyPUSDConvex.sol
• _massUpdatePools() in LPFarming.sol
• _claimAll() in LPFarming.sol

3. != 0 is More Efficient than > 0 in Require Statements

within require statements, != comparisons are slightly more gas efficient than > and when a uint is being compared to 0, != is effectively the same as > 0.

Locations:

• contracts/farming/LPFarming.sol::114 => require(_rewardPerBlock > 0, "Invalid reward per block");
• contracts/farming/LPFarming.sol::218 => require(_amount > 0, "invalid_amount");
• contracts/farming/LPFarming.sol::239 => require(_amount > 0, "invalid_amount");
• contracts/farming/LPFarming.sol::337 => require(rewards > 0, "no_reward");
• contracts/farming/LPFarming.sol::354 => require(rewards > 0, "no_reward");
• contracts/farming/yVaultLPFarming.sol::101 => require(_amount > 0, "invalid_amount");
• contracts/farming/yVaultLPFarming.sol::118 => require(_amount > 0, "invalid_amount");
• contracts/farming/yVaultLPFarming.sol::139 => require(rewards > 0, "no_reward");
• contracts/lock/JPEGLock.sol::40 => require(_newTime > 0, "Invalid lock time");
• contracts/staking/JPEGStaking.sol::32 => require(_amount > 0, "invalid_amount");
• contracts/vaults/FungibleAssetVaultForDAO.sol::108 => require(answer > 0, "invalid_oracle_answer");
• contracts/vaults/FungibleAssetVaultForDAO.sol::142 => require(amount > 0, "invalid_amount");
• contracts/vaults/FungibleAssetVaultForDAO.sol::164 => require(amount > 0, "invalid_amount");
• contracts/vaults/FungibleAssetVaultForDAO.sol::180 => require(amount > 0, "invalid_amount");
• contracts/vaults/FungibleAssetVaultForDAO.sol::194 => require(amount > 0 && amount <= collateralAmount, "invalid_amount");
• contracts/vaults/NFTVault.sol::280 => require(_newFloor > 0, "Invalid floor");
• contracts/vaults/NFTVault.sol::367 => require(pendingValue > 0, "no_pending_value");
• contracts/vaults/NFTVault.sol::464 => require(answer > 0, "invalid_oracle_answer");
• contracts/vaults/NFTVault.sol::689 => require(_amount > 0, "invalid_amount");
• contracts/vaults/NFTVault.sol::766 => require(_amount > 0, "invalid_amount");
• contracts/vaults/NFTVault.sol::772 => require(debtAmount > 0, "position_not_borrowed");
• contracts/vaults/NFTVault.sol::884 => require(position.liquidatedAt > 0, "not_liquidated");
• contracts/vaults/NFTVault.sol::928 => require(position.liquidatedAt > 0, "not_liquidated");
• contracts/vaults/yVault/strategies/StrategyPUSDConvex.sol::335 => require(wethBalance > 0, "NOOP");
• contracts/vaults/yVault/yVault.sol::143 => require(_amount > 0, "INVALID_AMOUNT");
• contracts/vaults/yVault/yVault.sol::167 => require(_shares > 0, "INVALID_AMOUNT");
• contracts/vaults/yVault/yVault.sol::170 => require(supply > 0, "NO_TOKENS_DEPOSITED");